Such feed pumps are often used, for example in present-day motor vehicles, for feeding fuel or windshield cleaning fluid and are known from practice. The impeller of the feed pump is fastened on a shaft of an electric motor. The feed pump has as an axial bearing, in a radially inner region of the impeller, as seen from the vane chambers, interconnected pockets for collecting the fluid to be fed by the pump. These pockets form, with the fluid, an axial plain bearing.
One disadvantage of the known feed pump is that the impeller and consequently the shaft driving the impeller are subjected to very high load in the radial direction, since the pressure within the feed chamber is substantially higher in the region of the outlet duct than in the -region of the inlet duct. This leads to very high friction in bearings of the impeller. Moreover, the friction reduces the efficiency of the feed pump.